In Martian Child, John costars opposite Amanda Peet as an adoptive dad to Dennis, an unusual but charming little boy who believes he's from Mars. On working with 10-year-old Bobby Coleman, John explains, "We sort of got to know each other like in the movie. They start out as strangers when David adopts him, and we just let the relationship unfold as it went on. You have to be very careful about the rules that apply to actors because they sort of apply even more so [with children]. Any actor needs concentration and a quiet space to work and everybody needs to be focused, so when you have a younger actor involved, it just makes it an even better place to work."